JP6800062B2 - Adhesive tape - Google Patents

Description

INDUSTRIAL APPLICABILITY The present invention is an expandable adhesive tape that can be used to fix a semiconductor wafer or the like in a dicing step for dividing a semiconductor wafer or the like into chip-shaped elements, and can be used to divide the semiconductor wafer or the like into chips by expanding. Regarding.

Conventionally, in the manufacturing process of semiconductor devices such as integrated circuits (ICs), the back grind process of grinding the back surface of the wafer in order to thin the wafer after forming the circuit pattern, and the adhesive and stretchable back surface of the wafer. A dicing process that divides a wafer into chip units after attaching a certain adhesive tape, an expanding process that expands the adhesive tape, a pickup process that picks up the divided chips, and a lead frame or package for the picked up chips. A die bonding (mounting) step of adhering to a substrate or the like (or, in a stacked package, laminating and adhering chips to each other) is performed.

In the dicing step, an adhesive tape in which an adhesive layer is laminated on a base film is generally used. When such an adhesive tape is used, first, an adhesive layer of the adhesive tape is attached to the back surface of the wafer to fix the wafer, and the wafer is diced in chip units using a dicing blade. Then, by expanding the adhesive tape in the radial direction of the wafer, an expanding step of widening the distance between the chips is performed. This expanding step is carried out in order to improve the recognition of chips by a CCD camera or the like in the subsequent pick-up process and to prevent chip damage caused by contact between adjacent chips when picking up chips. To.

With the spread of IC cards in recent years, the thickness of semiconductor chips, which are the constituent members of IC cards, has been reduced. For this reason, it has become necessary to reduce the thickness of a wafer, which was conventionally about 350 μm, to 50 to 100 μm or less. As the wafer, which is a brittle member, becomes thinner, the risk of breakage during processing and transportation increases. When such an ultrathin wafer is cut by a dicing blade that rotates at a high speed as described above, there is a problem that chipping or the like occurs particularly on the back surface side of the semiconductor wafer, and the bending strength of the chip is significantly lowered.

For this reason, a so-called stealth dicing method has been proposed in which a dicing line is formed while selectively forming a modified region by irradiating the inside of the semiconductor wafer with a laser beam to cut the semiconductor wafer starting from the modified region. (Patent Document 1). According to the stealth dicing method, a laser beam is irradiated inside the semiconductor wafer to form a modified region, and then an ultrathin semiconductor wafer is attached to an adhesive tape and the adhesive tape is expanded to follow the dicing line. Semiconductor wafers can be divided (diced) to produce semiconductor chips with good yield.

According to the stealth dicing method described above, the wafer is cut in a non-contact manner by irradiating the laser beam and expanding the adhesive tape, so that the physical load on the wafer is small and the wafer is as in the case of currently mainstream blade dicing. Wafers can be cut without causing chipping. For this reason, it is attracting attention as an excellent technology that can replace blade dicing.

Japanese Patent No. 3762409

When a small-sized semiconductor chip is produced by using such a stealth dicing method, the number of lines between semiconductor chips called scribe lines increases, so that it is necessary to expand the adhesive tape to a larger extent. However, when it is greatly expanded, the adhesive tape is stretched more than usual, so that the conventional adhesive tape is peeled off from the ring frame fixing the adhesive tape, and the force is sufficiently transmitted to the modified region inside the wafer. Therefore, there is a problem that the wafer cannot be made into a chip with a good yield.

Therefore, according to the present invention, even if the wafer is greatly expanded by expanding in the individualization step, the force is sufficiently transmitted to the modified region inside the wafer without peeling from the ring frame, and the wafer can be chipped with a high yield. It is an object of the present invention to provide an adhesive tape.

In order to solve the above problems, the adhesive tape according to the present invention is an adhesive tape having a base film and an adhesive layer formed on at least one surface side of the base film, and has a 5% modulus of 6. The pressure is 5.5 MPa or less, and the integrated value of the probe tack test of the pressure-sensitive adhesive layer is 12 kPa or more.

The adhesive tape is preferably formed of an energy ray-curable pressure-sensitive adhesive composition in which the pressure-sensitive adhesive layer is cured by irradiating with energy rays.

Further, in the pressure-sensitive adhesive tape, it is preferable that the pressure-sensitive adhesive layer is formed of a pressure-sensitive adhesive composition containing an acrylic polymer.

Further, in the adhesive tape, it is preferable that the base film is made of polyolefin.

Further, the adhesive tape has a laser processing step of irradiating a portion of the semiconductor wafer to be divided with laser light to form a modified region as a fracture starting point inside the semiconductor wafer, and the adhesive layer is applied to the semiconductor wafer. It is preferably used in a method for individualizing a semiconductor wafer, which includes a step of attaching a tape to be attached and an individualizing step of individualizing the semiconductor wafer along a dividing line by expanding.

According to the present invention, even if the wafer is greatly expanded by expanding in the individualization step, the force is sufficiently transmitted to the modified region inside the wafer without peeling from the ring frame, and the wafer can be chipped with a high yield. ..

It is sectional drawing which shows typically the structure of the adhesive tape which concerns on embodiment of this invention. It is sectional drawing which shows typically the laser processing process in the method of individualizing a semiconductor wafer using the adhesive tape which concerns on Example of this invention. It is sectional drawing which shows typically the tape sticking process in the method of individualizing a semiconductor wafer using the adhesive tape which concerns on Example of this invention. It is sectional drawing which shows typically the individualizing process in the individualizing method of the semiconductor wafer using the adhesive tape which concerns on Example of this invention. It is sectional drawing which shows typically the pick-up process of the semiconductor chip using the adhesive tape which concerns on Example of this invention.

Hereinafter, embodiments of the present invention will be described in detail.

FIG. 1 is a cross-sectional view showing an adhesive tape 1 according to an embodiment of the present invention. The adhesive tape 1 of the present invention is used when individualizing along a dividing line starting from a modified region 7 (see FIG. 2) formed inside a semiconductor wafer 6 (see FIG. 2) by expansion. is there. The adhesive tape 1 has a base film 2 and an adhesive layer 3 provided on the base film 2. In the adhesive tape 1, a separator 4 may be provided on the adhesive layer 3 in order to improve the handleability of the adhesive layer 3.

The adhesive tape 1 has a 5% modulus of 6.5 MPa or less, and the integrated value of the probe tack test of the adhesive layer 3 is 12 kPa or more. When the pressure-sensitive adhesive layer 3 is formed of an energy ray-curable pressure-sensitive adhesive composition described later, the 5% modulus of the pressure-sensitive adhesive tape 1 and the probe tack test of the pressure-sensitive adhesive layer 3 are performed before and after the energy ray irradiation. The integrated value may change. The individualizing step by expanding is usually performed before the energy ray irradiation, but may be performed after the energy ray irradiation. Therefore, the integrated value of the 5% modulus of the adhesive tape 1 and the probe tack test of the adhesive layer 3 defined in the present invention is usually the physical property value before the energy ray irradiation, but satisfies the above physical property value after the energy ray irradiation. Adhesive tapes to be used are also included in the scope of the present invention. It is important to satisfy the above physical property values in the individualizing step by expanding.

The base film 2 and the pressure-sensitive adhesive layer 3 are preferably cut (pre-cut) into a shape corresponding to the ring frame 8 (see FIG. 3 and the like) used when the semiconductor wafer 6 is separated into individual pieces. .. Further, the adhesive tape 1 of the present invention may be in the form of being cut for each wafer, or a long separator 4 in which a plurality of those cut for each wafer are formed. It may be wound into a shape. The configuration of each layer will be described below.

<Base film>
When the base film 2 has uniform and isotropic expandability, it is preferable that the wafer can be cut evenly in all directions in the individualizing step by expanding. As for the material, 5% modulus of the adhesive tape 1 is used. It is not particularly limited as long as it is 6.5 MPa or less.

Regarding the resin constituting the base film 2, for example, polypropylene, high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), ethylene / propylene copolymer, propylene copolymer, etc. Ethylene-propylene-diene copolymer sulfide, polybutene, polybutadiene, polymethylpentene, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) methyl acrylate copolymer, ethylene- (meth) acrylic acid Ethyl copolymer, ethylene-(meth) butyl acrylate copolymer, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, ethylene-vinyl chloride-vinyl acetate copolymer, polyurethane, polyamide, ionomer, nitrile rubber, Butyl rubber, styrene isoprene rubber, styrene butadiene rubber, natural rubber and its water additive or modified product may be used.

Above all, the base film 2 is preferably made of polyolefin because it exhibits excellent extensibility at the time of expansion. Examples of polyolefins include polyethylene, polypropylene, ethylene-propylene copolymer, polybutene-1, poly-4-methylpentene-1, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and methyl ethylene-acrylate. Examples thereof include copolymers, homopolymers or copolymers of α-olefins such as ethylene-acrylic acid copolymers and ionomers, or mixtures thereof.

In particular, in the case of the base film 2 in which the ionomer is used, uniform physical properties can be obtained in the feeding direction and the width direction of the base film 2. Therefore, it is possible to make the individualized chip intervals uniform when the expansion is performed.

In the example shown in FIG. 1, the base film 2 is a single layer, but the present invention is not limited to this, and a multi-layer structure in which two or more kinds of resins are laminated may be used, or one kind of resin may be used. It may be laminated in two or more layers. Two or more kinds of resins are preferable from the viewpoint that their respective characteristics are further enhanced and expressed if the crosslinkability and the non-crosslinkability are unified, and when the crosslinkable or non-crosslinkable properties are combined and laminated, each of them It is preferable in that the drawbacks of

If it is too thin, it is difficult to handle, and if it is too thick, the cost increases. Therefore, 50 to 200 μm is preferable, and 80 to 150 μm is more preferable.

As a method for producing the multi-layer base film 2, a conventionally known extrusion method, laminating method, or the like can be used. When the laminating method is used, an adhesive may be interposed between the layers. As the adhesive, a conventionally known adhesive can be used.

The surface of the base film 2 in contact with the pressure-sensitive adhesive layer 3 may be subjected to a corona treatment or a treatment such as a primer in order to improve the adhesion.

<Adhesive layer>
In the pressure-sensitive adhesive tape 1 of the present invention, the pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer 3 is not particularly limited as long as the integrated value of the probe tack test of the pressure-sensitive adhesive layer 3 is 12 kPa or more.

The pressure-sensitive adhesive layer 3 can be formed by various pressure-sensitive adhesive compositions. For example, a pressure-sensitive adhesive composition based on a rubber-based polymer such as natural rubber or various synthetic rubbers, an acrylic-based, a silicone-based, or a polyvinyl ether-based polymer is used. Among these, it is preferable to use an acrylic polymer, for example, a poly (meth) acrylic acid alkyl ester, or a copolymer of a (meth) acrylic acid alkyl ester and another unsaturated monomer copolymerizable therewith. ..

In order to add cohesive force to these resin components, a cross-linking agent can be added to the pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer 3. As the cross-linking agent, a cross-linking agent having a functional group capable of reacting with the functional group corresponding to the functional group in the resin component is appropriately selected to impart cohesive force to the pressure-sensitive adhesive and initial adhesion. The force can be set to the desired value. Examples of the cross-linking agent include isocyanate-based cross-linking agents, epoxy-based cross-linking agents, metal chelate-based cross-linking agents, aziridine-based cross-linking agents, and amine resins.

From the viewpoint of versatility, an isocyanate-based cross-linking agent is preferable as the cross-linking agent. Specifically, polyhydric isocyanate compounds such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylene diisocyanate, diphenylmethane-4,4'- Diisocyanate, diphenylmethane-2,4'-diisocyanate, 3-methyldiphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, lysine isocyanate and the like are used. ..

Further, the pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer 3 is an energy ray-curable pressure-sensitive adhesive composition that is cured by irradiating energy rays in order to improve the pick-up property after the semiconductor wafer 6 is separated into individual pieces. It is preferably a thing. Here, the energy ray means a light ray such as an ultraviolet ray or an ionizing radiation such as an electron beam.

As the energy ray-curable pressure-sensitive adhesive composition, for example, those described in Japanese Patent Application Laid-Open No. 1-56112, Japanese Patent Application Laid-Open No. 7-135189, etc. are preferably used, but the composition is not limited thereto.

In the present invention, it is preferable to use an ultraviolet curable pressure-sensitive adhesive composition. In that case, it suffices to have the property of being cured by radiation to form a three-dimensional network. For example, with respect to a normal rubber-based or acrylic-based pressure-sensitive resin component, at least two photopolymerizable carbons in the molecule. -A low molecular weight photopolymerizable compound having a carbon double bond (hereinafter referred to as a photopolymerizable compound) and a photopolymerization initiator can be blended.

Examples of the photopolymerizable compound include trimethyl propantriacrylate, tetramethylolmethanetetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, and 1,4-butylene. Examples thereof include glycol diacrylate, 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, organopolysiloxane composition, commercially available oligoester acrylate, and urethane acrylate.

As the resin component constituting the pressure-sensitive adhesive, one having a photocurable carbon-carbon double bond may be used. For example, an acrylic copolymer and / or a methacrylic copolymer (a1) having a photocurable carbon-carbon double bond with respect to a repeating unit of the main chain and having a functional group, and the functional group. Examples thereof include those obtained by reacting with a compound (a2) having a functional group capable of reacting. The acrylic copolymer and / or the methacrylic copolymer (a1) having a radiation-curable carbon-carbon double bond and having a functional group with respect to the repeating unit of the main chain is, for example, radiation-curable. A monomer (a1-1) such as an acrylic acid alkyl ester and / or a methacrylic acid alkyl ester having a sex carbon-carbon double bond and a monomer (a1-2) having a functional group are copolymerized. Obtainable.

As the monomer (a1-1), for example, a (meth) acrylic acid alkyl ester having 6 to 12 carbon atoms in the alkyl group of the alkyl ester (for example, hexyl acrylate, n-octyl acrylate, isooctyl acrylate, 2- Ethylhexyl acrylate, dodecyl acrylate, decyl acrylate) can be mentioned. Further, a (meth) acrylic acid alkyl ester having 5 or less carbon atoms in the alkyl group of the alkyl ester (for example, pentyl acrylate, n-butyl acrylate, isobutyl acrylate, ethyl acrylate, methyl acrylate, or a methacrylate similar thereto) can be used. Can be mentioned.

Examples of the functional group contained in the monomer (a1-2) include a carboxyl group, a hydroxyl group, an amino group, a cyclic acid anhydride group, an epoxy group, and an isocyanate group. Specific examples of the monomer (a1-2) include, for example, acrylic acid, methacrylic acid, carcinic acid, itaconic acid, fumaric acid, phthalic acid, 2-hydroxyalkylacrylates, 2-hydroxyalkylmethacrylates, and the like. Glycol monoacrylates, glycol monomethacrylates, N-methylol acrylamide, N-methylol methacrylicamide, allyl alcohol, N-alkylaminoethyl acrylates, N-alkylaminoethyl methacrylates, acrylamides, methacrylic acids, maleic anhydride , Itaconic anhydride, Fumaric anhydride, Phthalic anhydride, Glysidyl acrylate, Glysidyl methacrylate, Allyl glycidyl ether, Some of the isocyanate groups of polyisocyanate compounds are hydroxyl groups or carboxyl groups and simple carbon-carbon double bonds. It is possible to enumerate those made of urethane in a metric.

When the functional group of (a2) is a carboxyl group or a cyclic acid anhydride group, examples of the functional group of (a1) include a hydroxyl group, an epoxy group, and an isocyanate group. When the functional group of (a2) is a hydroxyl group, examples of the functional group of (a1) include a cyclic acid anhydride group and an isocyanate group. When the functional group of (a2) is an amino group, examples of the functional group of (a1) include an epoxy group and an isocyanate group. When the functional group of (a2) is an epoxy group, examples of the functional group of (a1) include a carboxyl group, a cyclic acid anhydride group, and an amino group.

In the case of an ultraviolet curable pressure-sensitive adhesive, by mixing a photopolymerization initiator in the pressure-sensitive adhesive, the polymerization curing time by ultraviolet irradiation and the amount of ultraviolet irradiation can be reduced. Specific examples of such a photopolymerization initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl diphenyl sulfide, tetramethyl thiuram monosulfide, azobisisobutyronitrile, dibenzyl and diacetyl. Examples thereof include β-chloranthraquinone.

The pressure-sensitive adhesive composition may contain various additive components, if desired, as long as the object of the present invention is not impaired. For example, known additives such as tackifiers, anti-aging agents, fillers, colorants, flame retardants, antistatic agents, softeners, UV absorbers, antioxidants, plasticizers, surfactants, etc. are included. May be. Moreover, you may add an inorganic compound filler as appropriate.

The thickness of the pressure-sensitive adhesive layer 3 is not particularly limited, but is preferably 4 to 30 μm, particularly preferably 5 to 25 μm.

The pressure-sensitive adhesive layer 3 can be formed by using a conventional method for forming a pressure-sensitive adhesive layer. For example, a method of applying the pressure-sensitive adhesive composition to a predetermined surface of the base film 2 to form the pressure-sensitive adhesive composition, or applying the pressure-sensitive adhesive composition to a separator (for example, a plastic film or sheet coated with a release agent). ), And then the pressure-sensitive adhesive layer 3 is transferred onto a predetermined surface of the base material, so that the pressure-sensitive adhesive layer 3 can be formed on the base material film 2. The pressure-sensitive adhesive layer 3 may have a single-layered form or may have a laminated form.

<Separator>
The separator 4 is for improving the handleability of the pressure-sensitive adhesive layer 3 and protecting the pressure-sensitive adhesive layer 3. The separator 4 used in the adhesive tape 1 of the present embodiment includes polyester (PET, PBT, PEN, PBN, PTT) -based, polyolefin (PP, PE) -based, copolymer (EVA, EEA, EBA) -based, and Further, a film having further improved adhesiveness and mechanical strength can be used by partially substituting these materials. Further, it may be a laminate of these films.

The thickness of the separator 4 is not particularly limited and may be set as appropriate, but is preferably 25 to 50 μm.

The pressure-sensitive adhesive layer 3 has an integrated value of 12 kPa or more in the probe tack test. The integrated value of the probe tack test can be obtained by using, for example, the tacking tester TAC-II of Reska Co., Ltd. Specifically, the pressure-sensitive adhesive layer 3 of the pressure-sensitive adhesive tape 1 is placed on top, and a probe made of SUS304 having a diameter of 3.0 mm is brought into contact with the pressure-sensitive adhesive layer 3 from above. The speed at which the probe is brought into contact with the measurement sample is 30 mm / min, the contact load is 0.98 N, and the contact time is 1 second. Then, the probe is peeled upward at a peeling speed of 600 mm / min, the force required for peeling is measured, and the integrated value is obtained. The measurement temperature is 23 ° C.

If the integrated value of the probe tack test of the pressure-sensitive adhesive layer 3 is less than 12 kPa, when the pressure-sensitive adhesive tape 1 is greatly expanded in the step of individualizing by expanding, the pressure-sensitive adhesive strength is insufficient and the pressure-sensitive adhesive tape 1 is peeled off from the ring frame. The semiconductor wafer 6 cannot be divided.

The adhesive tape 1 has a 5% modulus of 6.5 MPa or less. The 5% modulus of the adhesive tape 1 can be measured using a tensile strength tester in accordance with JIS K 7127/2/300, for example, using a strograph tester manufactured by Toyo Seiki Seisakusho Co., Ltd. can do. The 5% modulus is a tensile test of a 25 mm wide strip-shaped sample of adhesive tape 1 under the conditions of a temperature of 23 ° C., a relative humidity of 50%, a distance between marked lines and a distance between grips of 100 mm, and a tensile speed of 300 mm / min. Is performed, and the stress at the time of 5% strain is measured.

If the 5% modulus of the adhesive tape 1 is larger than 6.5 MPa, the adhesive tape 1 is peeled off from the ring frame due to the stress of the adhesive tape 1 due to the expansion, so that the semiconductor wafer 6 cannot be divided.

<Use>
The adhesive tape 1 of the present invention is an individual piece of the adhesive tape 1 of the present invention along a dividing line starting from a modified region 7 (see FIG. 2) formed inside a semiconductor wafer 6 (see FIG. 2) by expansion. It is used in a method for manufacturing a semiconductor device including a step of individualizing. Therefore, the other steps and the order of the steps are not particularly limited. For example, it can be suitably used in the following semiconductor device manufacturing methods (A) and (B).

Manufacturing method of semiconductor device (A)
(A) A step of attaching a surface protective tape to the surface of the wafer on which the circuit pattern is formed, and
(B) A back grind process for grinding the back surface of the wafer and
(C) A tape attaching step of attaching the adhesive layer of the adhesive tape to the back surface of the wafer, and
(D) A step of peeling the surface protective tape from the wafer surface and
(E) A laser processing step of irradiating a portion of the wafer to be divided with a laser beam to form a modified region by absorbing multiple photons inside the wafer.
(F) An individualizing step of dividing the wafer along a dividing line by expanding the adhesive tape to obtain a plurality of chips.
(G) A step of picking up the chip from the adhesive layer of the adhesive tape and
A method for manufacturing a semiconductor device including.

Manufacturing method of semiconductor device (B)
(A) A step of attaching a surface protective tape to the surface of the wafer on which the circuit pattern is formed, and
(B) A step of irradiating a portion of the wafer to be divided with a laser beam to form a modified region by absorbing multiple photons inside the wafer.
(C) A back grind process for grinding the back surface of the wafer and
(D) A tape attaching step of attaching the adhesive layer of the adhesive tape to the back surface of the wafer, and
(E) A step of peeling the surface protective tape from the wafer surface and
(F) An individualizing step of dividing the wafer along a dividing line by expanding the adhesive tape to obtain a plurality of chips.
(G) A step of picking up the chip from the adhesive layer of the adhesive tape and
A method for manufacturing a semiconductor device including.

<How to use>
A method of using the adhesive tape 1 when the adhesive tape 1 of the present invention is applied to the manufacturing method (B) of the semiconductor device will be described with reference to FIGS. 2 to 5.

First, a surface protection tape 13 (see FIG. 2) for protecting a circuit pattern, which contains an ultraviolet curable component in an adhesive, is attached to the surface of the semiconductor wafer 6 on which the circuit pattern is formed, and the back surface of the semiconductor wafer 6 is pressed. Perform a back grind process to grind.

After the completion of the backgrinding step, as shown in FIG. 2, the semiconductor wafer 6 is irradiated with laser light to form a modified region 7 by absorbing multiple photons inside the semiconductor wafer 6.

Next, the adhesive tape 1 is attached to the back surface of the semiconductor wafer 6. The pressure-sensitive adhesive layer 3 of the pressure-sensitive adhesive tape 1 and the back surface of the semiconductor wafer 6 are bonded together, and the outer peripheral portion of the pressure-sensitive adhesive layer 3 and the ring frame 8 (see FIG. 3) are bonded together.

Next, the semiconductor wafer 6 to which the adhesive tape 1 is attached is placed on a suction table (not shown) with the adhesive tape 1 side down. Then, from above the semiconductor wafer 6 adsorbed and fixed to the adsorption table, for example, 1000 mJ / cm ² of ultraviolet rays is irradiated to the substrate surface side of the surface protective tape 13 using an energy ray light source, and the semiconductor of the surface protective tape 13 is irradiated. The adhesive force to the wafer 6 is reduced, and the surface protective tape 13 is peeled off from the surface of the semiconductor wafer 6. As a result, as shown in FIG. 3, the ring frame 8 holds the adhesive tape 1 to which the semiconductor wafer 6 provided with the modified region 7 is attached.

Next, the adhesive tape 1 to which the semiconductor wafer 6 provided with the modified region 7 is attached to the ring frame 8 is placed on a stage (not shown) of the expanding device with the base film 2 side facing down. Place.

Next, as shown in FIG. 4, with the ring frame 8 fixed, the hollow cylindrical push-up member 10 of the expanding device is raised to expand (expand) the adhesive tape 1. As the expansion conditions, the expanding speed is, for example, 5 to 500 mm / sec, and the expanding amount (pushing amount) is, for example, 5 to 25 mm. By stretching the adhesive tape 1 in the radial direction of the semiconductor wafer 6 in this way, the semiconductor wafer 6 is divided into 9 chip units starting from the modified region 7.

After that, the pressure-sensitive adhesive layer 3 is subjected to an energy ray curing treatment, a thermosetting treatment, or the like to weaken the adhesive force of the pressure-sensitive adhesive layer 3 on the semiconductor wafer 6, and then the chip 9 is placed on the base film 2 side as shown in FIG. It is pushed up by the push-up pin 11 and picked up by the suction collet 12.

<Example>
Next, in order to further clarify the effect of the present invention, Examples and Comparative Examples will be described in detail, but the present invention is not limited to these Examples.

(1) Preparation of base film <Base film 1>
Using an ethylene-vinyl acetate copolymer (trade name "NUC-3660" manufactured by NUC Co., Ltd.), the base film 1 is melted at 140 ° C. and molded to a thickness of 100 μm using an extruder. Created.
<Base film 2>
Ethylene-methacrylic acid- (2-methyl-propyl acrylate) -Zn ++ ionomer resin (manufactured by Mitsui DuPont Polychemical Co., Ltd., trade name "Himilan AM7316") is melted at 140 ° C and thickened using an extruder. The base film 2 was prepared by molding so that the thickness was 100 μm.
<Base film 3>
Polypropylene (manufactured by Prime Polymer Co., Ltd., trade name "F227D") was melted at 140 ° C. and molded using an extruder to a thickness of 100 μm to prepare a base film 3.

(2) Preparation of adhesive <Adhesive 1>
A polyisocyanate compound (Tosoh) with respect to 100 parts by mass of an acrylic base polymer (copolymer composed of 2-ethylhexyl acrylate, methyl acrylate, 2-hydroxyethyl acrylate, weight average molecular weight 300,000, glass transition point = -35 ° C). 2 parts by mass of Co., Ltd., trade name "Coronate L"), 75 parts by mass of tetramethylolmethanetetraacrylate as a compound having a photopolymerizable carbon-carbon double bond, and a photopolymerization initiator (manufactured by BASF, trade name "" Irgacure 184 ") was added and mixed by 1.5 parts by mass to obtain an acrylic pressure-sensitive adhesive 1.

<Adhesive 2>
A polyisocyanate compound (Tosoh) with respect to 100 parts by mass of an acrylic base polymer (copolymer composed of 2-ethylhexyl acrylate, methyl acrylate, 2-hydroxyethyl acrylate, weight average molecular weight 300,000, glass transition point = -35 ° C). 3 parts by mass of Co., Ltd., trade name "Coronate L"), 50 parts by mass of tetramethylolmethanetetraacrylate as a compound having a photopolymerizable carbon-carbon double bond, and a photopolymerization initiator (manufactured by BASF, trade name "" Irgacure 184 ") 1.5 parts by mass was added and mixed to obtain an acrylic pressure-sensitive adhesive 2.

(3) Preparation of Adhesive Tape <Example 1>
The pressure-sensitive adhesive composition in which the pressure-sensitive adhesive 1 was dissolved in ethyl acetate and stirred was applied to a release liner made of a release-treated polyethylene-terephthalate film so that the thickness after drying was 10 μm, and the pressure was changed to 3 at 110 ° C. After drying for a minute, it was bonded to the base film 1 to prepare an adhesive tape according to Example 1 in which an adhesive layer was formed on the base film.

<Example 2, Comparative Examples 1 to 3>
The adhesive tapes according to Example 2 and Comparative Examples 1 to 3 were prepared by the same method as in Example 1 except that the thicknesses of the base film, the pressure-sensitive adhesive, and the pressure-sensitive adhesive layer were combined as shown in Table 1. ..

The 5% modulus of the adhesive tape, the integral value of the probe tack test of the adhesive layer, the breakability of the semiconductor wafer, and the peeling of the adhesive tape from the ring frame according to the examples and comparative examples were measured and evaluated as follows. It was. The results are shown in Table 1.

(4) Measurement of 5% Modulus Value A 25 mm wide strip-shaped sample was prepared for the adhesive tape according to Examples and Comparative Examples. The strip-shaped sample is tensioned in accordance with JIS K 7127/2/300 under the conditions of a temperature of 23 ° C. and a relative humidity of 50%, a distance between marked lines and a distance between grips of 100 mm, and a tensile speed of 300 mm / min. A test was performed and the stress at 5% strain was measured. A strograph tester manufactured by Toyo Seiki Seisakusho Co., Ltd. was used for the measurement.

(5) Integral value of probe tack test This was performed using the tacking tester TAC-II of Reska Co., Ltd. As the measurement mode, "Constant Road" was used, in which the probe was pushed to the set pressurization value and the pressurization value was maintained until the set time elapsed. The adhesive layer of the adhesive tape was turned up, and a probe made of SUS304 having a diameter of 3.0 mm was brought into contact with the probe from the upper side. The speed at which the probe is brought into contact with the measurement sample is 30 mm / min, the contact load is 0.98 N, and the contact time is 1 second. Then, the probe was peeled upward at a peeling speed of 600 mm / min, the force required for peeling was measured, and the integrated value was read. The probe temperature was 23 ° C. and the plate temperature was 23 ° C.

(6) Peeling from the ring frame A semiconductor wafer (thickness 50 μm, diameter 300 mm) on which a circuit pattern was formed was irradiated with laser light to form a modified region inside the wafer. Adhesive tape was laminated on the semiconductor wafer and the stainless steel ring frame after laser irradiation. Next, the ring frame was fixed by the expanding device, and the adhesive tape was expanded under the following expanding conditions.
Expanding speed: 300 mm / min
Expanding amount: 25 mm
Here, the expanding amount refers to the amount of change in the relative positions of the ring frame and the push-up member before and after pressing down.
The chip size is 0.5 mm × 0.5 mm.

After performing the above expansion, the adhesive tape was visually observed, and those that did not peel off from the ring frame were marked as "○" as good products, and those that were partially peeled as "×" were marked as defective. evaluated.

(7) Wafer fragmentation After performing the above expansion, whether or not the semiconductor wafer is divided into chips is observed with an optical microscope, and those that are all divided are marked with "○" as non-defective products, and even a part of them is divided. Those that were not marked as defective were evaluated as "x".

As shown in Table 1, in Examples 1 and 2, the 5% modulus of the adhesive tape is 6.5 MPa or less, and the integrated value of the probe tack test of the adhesive layer is 12 kPa or more, so that the wafer breakability and the ring Good results were obtained in the evaluation of peeling from the frame.

On the other hand, in Comparative Example 1, since the 5% modulus of the adhesive tape is larger than 6.5 MPa and the integrated value of the probe tack test of the adhesive layer is less than 12 kPa, the evaluation of wafer breakability and peeling from the ring frame is inferior. The result was. In Comparative Example 2, the 5% modulus of the adhesive tape was larger than 6.5 MPa, and the adhesive tape was peeled from the ring frame due to the stress applied to the adhesive tape during expansion, so that the evaluation of wafer breakability and peeling from the ring frame was inferior. The result was. In Comparative Example 3, the integrated value of the probe tack test of the pressure-sensitive adhesive layer was less than 12 kPa, and the adhesive tape peeled off from the ring frame during expansion due to insufficient adhesive strength. Therefore, in the evaluation of wafer breakability and peeling from the ring frame. The result was inferior.

1: Adhesive tape 2: Base film 3: Adhesive layer 6: Semiconductor wafer 7: Modified region 8: Ring frame

Claims (2)

An adhesive tape having a base film and an adhesive layer formed on at least one surface side of the base film.
5% modulus is 6.5 MPa or less,
The base film is made of polyolefin and is made of polyolefin.
The pressure-sensitive adhesive layer is formed of an energy ray-curable pressure-sensitive adhesive composition containing an acrylic polymer and cured by irradiation with energy rays.
An adhesive tape characterized in that the integrated value of the probe tack test of the pressure-sensitive adhesive layer is 12 kPa or more. A laser processing step of irradiating a portion of a semiconductor wafer to be divided with a laser beam to form a modified region as a starting point of fracture inside the semiconductor wafer.
A tape application step of attaching the pressure-sensitive adhesive layer to the semiconductor wafer, and
The adhesive tape according to claim 1, wherein the adhesive tape is used in a method for individualizing a semiconductor wafer, which includes an individualizing step of individualizing the semiconductor wafer along a dividing line by expanding .